Section 306. Evidence

1.  Irrelevant  or  unduly repetitious evidence or
  cross-examination may be  excluded.  Except  as  otherwise  provided  by
  statute,  the  burden  of  proof shall be on the party who initiated the
  proceeding. No decision, determination or order  shall  be  made  except
  upon  consideration  of the record as a whole or such portion thereof as
  may be cited by any party to the proceeding and as supported by  and  in
  accordance  with  substantial evidence. Unless otherwise provided by any
  statute, agencies need not observe the rules  of  evidence  observed  by
  courts,  but  shall  give effect to the rules of privilege recognized by
  law.  Objections to evidentiary offers may be made and shall be noted in
  the record.   Subject to these requirements,  an  agency  may,  for  the
  purpose  of  expediting hearings, and when the interests of parties will
  not be  substantially  prejudiced  thereby,  adopt  procedures  for  the
  submission of all or part of the evidence in written form.
    2.  All evidence, including records and documents in the possession of
  the agency of which it desires to avail itself,  shall  be  offered  and
  made  a  part  of  the  record, and all such documentary evidence may be
  received in the form of copies  or  excerpts,  or  by  incorporation  by
  reference.  In  case  of  incorporation  by  reference, the materials so
  incorporated shall be available for examination by  the  parties  before
  being received in evidence.
    3. A party shall have the right of cross-examination.
    4.  Official notice may be taken of all facts of which judicial notice
  could be taken and of other facts within the  specialized  knowledge  of
  the  agency.    When  official  notice  is  taken of a material fact not
  appearing in the evidence in the record and  of  which  judicial  notice
  could  not be taken, every party shall be given notice thereof and shall
  on timely request be  afforded  an  opportunity  prior  to  decision  to
  dispute the fact or its materiality.